| CADR (Clean Air Delivery Rate) | Standardized measure (ANSI/AHAM AC-1) indicating volume of contaminant-free air delivered per minute in cubic feet (CFM). |
| True HEPA H13 (EN 1822) | High Efficiency Particulate Air medium capturing at least 99.95% of particles at the Most Penetrating Particle Size (MPPS). |
| True HEPA H14 (EN 1822) | Medical-grade cleanroom medium capturing at least 99.995% of particles at MPPS with zero aerosol bypass leakage. |
| MPPS (Most Penetrating Particle Size) | Particle aerodynamic diameter (typically 0.12 - 0.25 µm) where diffusion and impaction collection efficiencies are minimized. |
| Brownian Diffusion | Random thermal jitter motion of sub-0.1µm nanoparticles colliding with air gas molecules, causing capture by filter fibers. |
| Inertial Impaction | Capture mechanism for particles >1.0µm whose momentum prevents following curving streamlines around filter fibers. |
| Interception | Capture mechanism where a particle follows laminar streamline but touches fiber boundary due to its finite physical radius. |
| Electrostatic Electret Media | Dielectric polymer fibers embedded with permanent quasi-static electric charges to enhance particle attraction. |
| VOC (Volatile Organic Compounds) | Carbon-based gaseous chemicals with high vapor pressure at room temperature that pass directly through HEPA filters. |
| Gas-Phase Adsorption | Physical condensation and capture of gas molecules onto internal pore surfaces of activated carbon via Van der Waals forces. |
| Chemisorption | Chemical bonding and irreversible reaction between gas contaminants and impregnated oxidants like potassium permanganate (KMnO4). |
| CARB (California Air Resources Board) | State regulatory agency enforcing mandatory indoor air cleaner ozone safety limits (<0.050 ppm) under UL 867. |
| UL 867 Standard | Underwriters Laboratories safety certification evaluating electrical insulation and ozone emissions in residential air cleaners. |
| UL 2998 Zero Ozone Validation | Environmental safety standard verifying indoor air cleaning appliances produce less than 0.005 ppm (5 ppb) ozone. |
| ACH (Air Changes per Hour) | Number of times total volumetric air content of a room is fully cycled through the air cleaner media in 60 minutes. |
| AHAM 2/3 Rule | Rule of thumb requiring minimum Smoke CADR rating to equal at least two-thirds (66.7%) of room floor area in square feet. |
| PM2.5 (Fine Particulate Matter) | Airborne combustion and smoke particles with aerodynamic diameter equal to or smaller than 2.5 micrometers. |
| PM10 (Coarse Particulate Matter) | Airborne dust, pollen, and mold fragments with aerodynamic diameter equal to or smaller than 10 micrometers. |
| PM0.1 (Ultrafine Nanoparticles) | Airborne combustion aerosols under 100 nanometers that penetrate alveolar barriers directly into the human bloodstream. |
| Static Pressure Drop (ΔP) | Resistance to airflow across filter media measured in Pascals (Pa) or inches of water column (in. w.g.). |
| BLDC (Brushless DC Motor) | Electronically commutated motor offering 60-80% lower power consumption and whisper-quiet bearing acoustics. |
| Backward-Curved Centrifugal Impeller | Fan geometry designed to maintain high volumetric CFM against the rising static pressure of loaded HEPA filters. |
| Sound Pressure Level (Lp in dBA) | Acoustic pressure measured at a fixed distance (1.0 meter) weighted to human ear auditory sensitivity curve. |
| Sound Power Level (Lw in dBA) | Total acoustic sound energy emitted by an appliance in all directions independent of measurement distance. |
| Bypass Leakage | Unfiltered airflow escaping around filter frame edges, gaskets, or housing seams that degrades overall air cleaner efficiency. |
| Filter Face Velocity | Speed at which air passes through the frontal surface area of the filter medium, typically 0.05 to 0.25 m/s in HEPA. |
| Pleat Depth & Spacing | Geometric folding of filter media to pack 15 to 40 square feet of surface area into a compact 1.5-inch chassis. |
| Virgin Coconut Shell Carbon | High-density activated carbon characterized by predominantly microporous structure (pores <2 nm) ideal for small gas molecules. |
| CTC Activity (Carbon Tetrachloride) | Standard ASTM test measuring micropore adsorption capacity; high-grade filter carbon carries 60% to 80% CTC activity. |
| Secondary Organic Aerosol (SOA) | Particulates formed in indoor air when ozone reacts with terpenes from pine cleaners, scented candles, or citrus oils. |
| Condensation Particle Counter (CPC) | Metrological laser instrument that enlarges nanoparticles via alcohol condensation to count down to 1 nanometer. |
| Optical Particle Sizer (OPS) | Laser scatter spectrometer measuring airborne particle count concentrations sorted into 16 discrete size channels. |
| Building Infiltration Rate | Rate of unconditioned outside air leaking through wall joints, windows, and gaps, typically 0.35 to 1.2 ACH in homes. |
| ASHRAE Standard 52.2 | Standardized test procedure evaluating fractional particle size efficiency of general ventilation air cleaning devices. |
| MERV (Minimum Efficiency Reporting Value) | Scale from 1 to 16 rating filter performance; HEPA exceeds MERV 16 (often designated MERV 17 to 20). |
